How Much Home Grow to Allow in Legal Marijuana States?

When your state legalizes marijuana, how should the new repel law be written? Specifically, on the key question of home grow, how many plants should you be able to grow for yourself and friends?

In one sense, the answer is obvious — as many as you want. If it’s legal, why should it matter to anyone how many? The law should not specify ANY number: “It shall be legal to possess, to use, and to produce for non-commercial distribution.”